Dental wedge

ABSTRACT

An improved dental wedge for use in applying pressure between the teeth is disclosed in the form of a resilient, open-sided, trihedron-like body formed of synthetic plastic material.

United States Patent 1 [111 3,890,714 Gores June 24, 1975 DENTAL WEDGE 193,094 7/[965 Schulstad 32/64 [76] Inventor: Kenneth W. Gores, 1026 ll2th NE, Bellevue, Wash. 98004 [22] Filed: Nov. 29, 1973 [21] Appl. No.: 419,954

Primary Examiner-Robert Peshock {57] ABSTRACT [52] US. Cl. 32/64 [51] Int. Cl. A6lc 3/00 An improved dental wedge for use in applying pres- [58] Field oi Search 32/64, 63 sure between the teeth is disclosed in the form of a resilient, open-sided, trihedron-like body formed of syn- [56] References Cited thetic plastic material.

UNITED STATES PATENTS 2,150,005 3/1939 McNinch 32/64 3 Claims, 8 Drawing Figures DENTAL WEDGE BACKGROUND OF THE INVENTION FIELD OF THE INVENTION decay or trauma approximated and contacted another w tooth in that arch it is necessary to confine the filling material during placement and until rigid enough to support itself by means of a thin strip of material (stainless steel or mylar) which encircles the tooth and is held tightly around the tooth by means of a strip retainer.

Because the tooth is usually bell shaped the band material tends to stand away from the tooth at its narrowed portion where it enters the gum tissue.

When this occurs the filling material is allowed to pass between the tooth edge and the band material producing an overhang which irritates the gum tissue, prevents the easy removal of debris and can contribute to a recurrence of decay.

To prevent this the dentist uses a wedge which is a triangular piece of wood or plastic which tapers to a point on one end. This is forced between the approximating teeth in the region between the contact point and the gingival tissue and causes the band material to be pressed against the gingival portion of the tooth at the floor of a preparation thereby closing the space and preventing the overhang.

The wedge performs a very vital secondary function in that it forces the teeth apart creating a slightly wider space between than would normally be present. This is important because the band material occupies a certain amount of space and after the filling is placed and the band is removed this space would persist unless the elastic memory of the periodental membrane moved the teeth closer together after the removal of the wedge which created the unnatural separation. While wedges of this invention are hereafter exemplarily described in respect of their use in connection with bands it is to be understood that this is not by way of limitation on the scope of the invention.

PRIOR PRACTICES If a tooth were sectioned at a level just apical to the crest of the gingiva it would be seen that its shape was somewhat circular. The gingival portion of the band then must be forced against a curved surface. The solid nature of present wedges results in little more than point contact between the wedge and the band and the tooth which could allow the filling material to be forced between the band and the tooth at the unstressed bandtooth area.

The interdental papilla occupies the space between the teeth into which the wedge is forced. Since two things cannot occupy the same space at the same time the tissue between the teeth is traumatically compressed causing a crushing type injury.

Because the material used in present wedges is only slightly deformable and has no elastic memory all of the force applied to separate the teeth is exerted at the instant of placement. This can result in trauma to the per iodontal membrane which separates the root surface of the tooth from the bone and is the attachment of the tooth to the bone. When the tooth has moved slightly in response to the pressure the force created by the wedge is immediately lost and no further movement occurs.

THE DRAWINGS DESCRIBED FIG. 1 is a perspective view, greatly enlarged, of a dental wedge according to this invention;

FIG. 2 is a longitudinal sectional view of the wedge of FIG. 1;

FIG. 3 is a typical cross-sectional view of the wedge;

FIG. 4 is a schematic perspective view showing a mode of using wedges in this invention;

FIG. 5 is an enlarged cross-sectional view of a pair of teeth showing a wedge placed in operable position therebetween;

FIG. 6 is a plan view ofa wedge in use;

FIG. 7 is a perspective view of an alternative simplified form of dental wedge; and

FIG. 8 is a cross-section of the wedge of FIG. 7.

DESCRIPTION OF THE INVENTION Referring to FIGS. 1, 2 and 3 the dental wedge 8 will. in this preferred form, be seen to comprise a pair of walls 10 and 12 vee-joined at apex 14 to define an open-sided trihedron-like body having a pointed end 16 and a broad rear end 18. Wall 20, in this preferred form, spans between walls 10,12 adjacent the broader or larger end of the open side of the body.

In FIG. 3 walls 10,12 are shown to be arranged chevronlike or divergent from the apical joint 14 to their free edges 22. Preferably walls 10,12 increase in thickness from edges 22 toward joint 14 (as shown). However, in some instances it is desirable that each wall 10,12 have uniform thickness between joint 14 and edges 22.

In FIG. 2 apex joint 14 is shown as having greater vertical thickness at the rear end 18 of the body 8 than at the pointed end or tip 16. Tip 16 is preferably slightly canted at 24 to facilitate placement of the wedge and to avoid injury to a patient as could occur upon penetration of the interdental papillae.

Wall 20 in the preferred form is shown externally concave or inwardly bowed between the paired walls 10,12. Wall 20 is operable to stabilize or stiffen walls 10,12 at the rear of the wedge body 8 when in use. and to facilitate placement and removal with cotton pliers. The concavity predetermines the direction of deformation caused by a force which tends to approximate paired walls 10,12 and adds increased resistance. Additionally. the inward bow of wall 20 may come into contact with the interdental papillae and prevent the wedge from passing completely through the interdental space.

MODE OF USE IN DENTISTRY In dentistry it is common practice to prepare a tooth for filling by shaping a cavity therein. and then encircling the tooth with a band drawn tightly therearound to contain the filling materials to be packed in said cavity. It is very important that the band be tightly pressed in its lower portion to the tooth being filled. The primary object of this invention is to provide a resilient dental wedge 8 for such purpose.

In FIG.4 is shown molar teeth 30,32,34 as they may appear in a persons mouth. Tooth 32 has a shaped and prepared cavity or void 36, in this case open at both ends. Elongated band 38 is passed around tooth 32 to encircle it. Means not shown draw the band close to the gingival floor of the prepared cavity. Bands in some instances are formed of sheet plastic and in other of very thin stainless steel. They are drawn tight by the use of pliers or more desirably. a clamp-screw device forming no part of this invention. Often it occurs that the lower portion of a band does not conform to the smaller gingival part of the tooth even though the band is tightly pressed against the tooth about its larger circumfer ence. In such circumstances a wedge 8 is placed between the proximate tooth 30 and band 38 and, as required. another wedge 8 between the other side of band 38 and another proximate tooth 34. Pressure applied by such wedges forces the band to assume close anatomical contact with the tooth at the level of the gingival floor of any cavity being filled.

In FIG. 5 in enlarged fragmentary cross-section is shown the teeth 30 and 32 with band 38 in place surrounding tooth 32. A portion of the cavity preparation 36. in this typical example. is seen to extend close to the gum line indicated at 40. The interdental papillae 42 is soft flesh which rises between the teeth. It is be lieved that two functions of the dental wedge will be illuminated from FIG. 5. Firstly the walls and 12, bearing respectively on tooth 30 and the lower portion of band 38, are compressed together and thus tensed to apply a reactive pressure against the band forcing it into contact with the tooth at the gum line. Secondly the open-side of wedge 8 being disposed over the papillae 42 accomodate the latter. Thus pressure on the papillae and pain or injury to the patient is avoided.

When the wedge 8 is introduced into the interdental space the walls 10 and 12 are compressed together in the most restricted region creating what may be called a pressure point". As wedge 8 is shoved deeper into an interdental gap the reactive force exerted by wedge 8 increases due to the greater spacing between the lower edges of walls 10 and 12. In those instances where walls 10 and 12 are tapered is shown in FIG. 3 the reactive force is increased in a geometrical progression. Further increases of the reactive forces may be controlled by thickening wedge 8 at apex 14 as seen in FIG. 2. Additionally wall at the rear end 18 of wedge 8, when used in a preferred design, bolsters the reactive pressure exerted by walls 10 and 12 when the wedge is deeply pressed into place. And still further the degree of concavity or bowing of wall 20 determines the force needed to collapse the walls 10 and 12.

The newer composite filling material now being widely adopted are tooth matching in color and are a mixture of two viscous pastes which when combined set to a very hard abrasion resistant, tooth colored restoration.

They have been recommended by some producers as suitable for posterior as well as anterior teeth. Their disadvantage in both instances is that at the time of placement the composite material is soft and viscous and cannot be made to exert pressure against the retaining band so as to effect contact with the approximating tooth as can be done with the less plastic silver amalgam. Additionally, the band cannot be removed until the composite is set at which time the filler material is very hard. Any overhanging material which might have passed between the band and the gingival floor of the cavity preparation is extremely difficult to remove.

Because no pressure can be exerted against the band by forceful packing of the soft composite material it is essential that the approximating tooth adjacent to the preparation and the tooth containing the preparation be forcefully separated prior to the placement of the composite. When the composite material has hardened the separating force can be removed and an adequate contact be secured between the composite and the approximating tooth. If this contact is not firm, stringy foods will pass between the teeth, creating the possibility of a pressure atrophy induced pocket which can eventually result in the loss of both teeth.

The design of this wedge. provides for the relatively atraumatic separation of approximating teeth by virtue of the resiliency of the material from which the wedge is made as well as the elastic memory provided by the design. These two features combine to provide a slow, increasing and constant force of separation as long as the wedge is in place as compared to the instantaneous separation caused by prior wedges, the force of which is lost as soon as the slightest separating movement of the teeth is achieved.

The edges 22 will tend to exert pressure along a greater segment of the circumference of the gingival portion of the tooth causing the band to be forced into approximation against the tooth more completely thereby reducing the possibility of the composite material (and silver amalgam for that matter) passing between the band and the floor of the gingival portion of the cavity preparation. The freedom of the thin edges 22 to conform to the contour of the tooth while continuing to exert the pressure needed for separation make this possible.

ALTERNATE WEDGE CONSTRUCTIONS In FIGS. 7 and 8 is shown a somewhat more simplitied form ofdental wedge 8. Walls 11 and 13 are of uniform thickness from their vee-joinder at apex 14 to their lower edges. Rear wall 20 has been omitted. There is in the FIGS. 7 and 8 form of the invention a certain amount of reactive pressure increase as this wedge is forced deeper into an interdental space. The increase however, is at a somewhat less progressive rate as compared with the wedge of FIGS. l3. There are circumstances where such effects are desirable.

Among the resilient and deformable materials from which dental wedges as herein may be formed are the synthetic plastics of which nylon and comparable plastics are suitable. A radio-opaque substance may be included in the plastic so that in the event a wedge is inadvertently swallowed or aspirated by a patient, its location may easily be determined by a fluoroscopic or x-ray examination.

In a practical form of these wedges the length measured along apex 14 was eleven-sixteenths of an inch, the width and height at rear end 18 was one eighth of an inch. The tapers of walls 10 and I2, and of apex 14 were in the proportion shown in the drawings. Larger and smaller versions of the presently preferred wedge are also contemplated, having proportional thickness and dimensional characteristics.

It has been found desirable to provide means to heighten the friction coefficient between the surfaces 12 of the wedge and adjacent tooth or band surfaces. In FIGS. 1 and 3 is shown outstanding ridges for such purpose. The slits 25 shown in FIG. 2 provide a toothlike action at the lower edges 22 for wedge retention. By canting or slanting the slits 25 as in FIG. 2, rearward directed teeth are provided. Another alternative (see FIG. 7) comprises providing pebbling 27 on the sloping outer surfaces 13. And further, scallops 28 on the lower edges of wedge may also be used.

In compliance with the statute, the invention has been described in language more or less specific as to structural features. It is to be understood, however, that the invention is not limited to the specific features shown. since the means and construction herein disclosed comprises a preferred form of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims, appropriately interpreted in accordance with the doctrine of equivalents.

What is claimed is:

l. A wedge for pressing the lower portion of a dental contour band to a tooth encircled thereby, comprising:

pliable means forming an elongated trihedron-like resilient body having an apex and an open side opposite thereto; said apex being formed by the junction of common edges of an angularly flaired pair of vee-joined, thin, triangular walls; each of said walls, in cross-section, tapering from said junction to its opposite edge; and a third wall fully closed the space between said paired walls adjacent the larger end of the open-side of said body said third wall providing a resilient resistance to collapse of said paired walls. 2. The structure of claim 1 in which said third wall is bowed inward between said paired walls.

3. The structure of claim 1 in which the planar walls include means to heighten the friction coefficient between said walls and surfaces with which contact occurs during use. 

1. A wedge for pressing the lower portion of a dental contour band to a tooth encircled thereby, comprising: pliable means forming an elongated trihedron-like resilient body having an apex and an open side opposite thereto; said apex being formed by the junction of common edges of an angularly flaired pair of vee-joined, thin, triangular walls; each of said walls, in cross-section, tapering from said junction to its opposite edge; and a third wall fully closed the space between said paired walls adjacent the larger end of the open-side of said body said third wall providing a resilient resistance to collapse of said paired walls.
 2. The structure of claim 1 in which said third wall is bowed inward between said paired walls.
 3. The structure of claim 1 in which the planar walls include means to heighten the friction coefficient between said walls and surfaces with which contact occurs during use. 